GB139406A - Improvements in valves and valve gears for internal combustion engines - Google Patents

Abstract

139,406. Hall, J. W. March 7, 1919. Valves; valve-gear.-Exhaust and scavenging ports 21 or 21, 22 at one end of the cylinder, and charge-inlet ports 23 or 23, 24 at the other end are controlled by a single sleeve valve 20 in the cylinder, so that air is drawn in during the first half of the suction stroke and expanded below atmospheric pressure, and a rich mixture is drawn in towards the end of the stroke; the compression and power strokes take place, in the usual manner; at the end of the power stroke, the charge-inlet port is closed and no exhaust gases can pass into the induction pipe; and during the exhaust stroke, a. draught of scavenging-air passes through the combustion chamber. The invention is shown as applied to a radial-cylinder engine comprising two sets of nine cylinders 1, 4 with the valve-gear arranged between them. The valve-gear comprises cam-grooves 40, 41 formed in the adjacent faces of crank-disks 31, 32 which run on rollers 28 in races 34. Each valves-rod 35, or 36, has a cross-head at its lower end, in which slides a shuttle 37; one end of the shuttle engages the groove in one cam-disk during the working and exhaust strokes, and in the other cam-disk during the suction and compression strokes, the grooves being inclined at their ends so as to transfer the shuttle from the one to the other. The grooves are found to effect the following movements r.f the valves, which are not the same during successive pairs of strokes. At the end of the working stroke, the sleeve port is below the inlet port and the sleeve is moving downwards and opening the exhaust. The sleeve reaches its lowest position at the end of the exhaust stroke with the exhaust fully opened, and scavenging-air is blown through the combustion chamber whilst the exhaust ports are opening either by the movement of the engine through the air or by means of a pump. During the first half of the suction stroke, whilst the exhaust ports are closing, air is drawn in; this air is then expanded below atmospheric pressure while the sleeve continues to move downwards. At the end of the suction stroke, the sleeve is stationary with the inlet ports in full register with the inlet ports in the cylinder, and the new charge is drawn in when the piston overruns the inlet ports.